Check every possible source for your cruise rates when booking. I checked on the Carnival website yesterday for our Victory booking. Entering my wife's info (she gets casino VIP mailings), past guest info, residence, and Military info (not quite seniors yet...), I got a set of rates that were pretty good.
I checked them against other online rates and the held up. The casino offer she had was out of date, so I didn't worry about it not showing at that point.
Once we made the decision to do the Victory cruise, I called and spoke with Carnival (I had to call as we were changing bookings--otherwise I might have just booked online). I told her all the rates that I was eligible for and she added the casino rate and another one to the mix.
To make a long story a little shorter, calling her saved another hundred or so buck off the cruise. It was a very good experience because she was a good rep. I've had bad ones; I just call back again.
I like to do everything myself but asking for a little help paid off this time...